Eric
Thanks for your response .
The Behringer DCX 2496 has a built in parametric EQ , I was always trying to tame the 300 to 500 hz by 3 to 6 db but I think like you said I should try in the upper bass 100 to 200 hz and I'll post the resuls .Concerning recordings I am pretty sure I use high end audiophile recordings and I get more or less the same problem .I also listened very close to the speakers to eliminate some of the room effects and it is certainly coming directly from the Mid/bass drivers , I dont know how much influence can the room have when you listen at 50 cm distance ?
Could the problem be the stuffing inside the enclosure ? mine is heavily stuffed .
thanks